Field of the Invention
The present disclosure relates to an electrophotographic photosensitive drum unit of a cartridge (a process cartridge) for use in an electrophotographic image forming apparatus and relates to a flange member for use in the electrophotographic photosensitive drum unit.
The electrophotographic image forming apparatus is an apparatus for use in forming an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include electrophotographic copiers, electrophotographic printers (for example, LED printers and laser beam printers), fax machines, and word processors.
The process cartridge is a combination of an electrophotographic photosensitive drum and a processing unit for the electrophotographic photosensitive drum and is detachably mounted in the electrophotographic image forming apparatus main body. One example is a combination of an electrophotographic photosensitive drum and at least one of a developing unit, a charging unit, and a cleaning unit (the processing unit).
Description of the Related Art
In the electrophotographic image forming apparatus (hereinafter simply referred to as “image forming apparatus”), an electrophotographic photosensitive member serving as an image bearing member, which is generally drum-shaped, is uniformly charged with electricity. Next, the charged electrophotographic photosensitive drum is selectively exposed to light to form an electrostatic latent image (an electrostatic image) on the electrophotographic photosensitive drum. Then, the electrostatic latent image formed on the electrophotographic photosensitive drum is developed into a toner image with toner serving as a developer. The toner image formed on the electrophotographic photosensitive drum is transferred to a recording medium, such as a recording sheet or a plastic sheet, the toner image transferred onto the recording medium is subjected to heat or pressure so that the toner image is fixed to the recording medium, and thus the image is printed.
Such image forming apparatuses generally need replenishing of toner and maintenance of the processing units. To facilitate the replenishing of toner and the maintenance, a process cartridge detachably mounted in an image forming apparatus main body is in practical use. The process cartridge contains, in a frame, the electrophotographic photosensitive drum, the charging unit, the developing unit, the cleaning unit, and so on.
This process cartridge system changes the operability because a user can perform maintenance by himself/herself, thus providing a usable image forming apparatus. This process cartridge system is widely used in image forming apparatuses.
The process cartridge employs a flange member integrally connected to the electrophotographic photosensitive drum. Japanese Patent Laid-Open No. 2015-079243 discloses portions (transmitted portions 87g) of the flange member subjected to a driving force transmitted from an image forming apparatus main body to a coupling member. This flange member works to transmit the driving force to the electrophotographic photosensitive drum.
If the flange member has low rigidity, the portion of the flange member subjected to the driving force from the coupling member rotates in a deformed state, and the amount of deformation can change with a change in load. The change in the amount of deformation of the flange member can change the rotational speed of the electrophotographic photosensitive drum unit, which can decrease the quality of an image formed by the electrophotographic image forming apparatus.